Grinder regulator system



Jan. 16, 1923. 1,442,042;

\ GRINDER REGULATOR SYSTEM. FILED sEPLH, 1920.

WITP-JESSES': INVENTOR W C/d/QNCQ A. 500072 71 5: WZM/ ATTORNEY Patented Jan. 16, 1923.

UNITED STATES PATENTv OFFICE.

CLARENCE A. BODDIE, OF PITTSBURGH, PENNSYLVANTA, AS SIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENN- sYLvANIa.

GRINDER REGULATOR SYSTEM.

Application filed September 11, 1920. Serial No. 409,717.

T 0 all whom it may concern:

Be it known that I, CLARENCE A. BODDI13, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Grinder Regulator Systems, of which the following is a -specification.

My invention relates to regulator systems and, particularly, to regulator systems for governing the operation of pulp grinders.

One object of my invention 18 to provide a regulator system of the above indicated character that shall control the load applied to a pulp grinder in a simple. and eflicient manner and that shall be provided with means for preventing hunting action.

In operating a pulp grinder, the wood, which is to be ground into pulp, is generally forced against the grinder by hydraulic pressure and such hydraulic pressure is varied to control the load on the grinder. The grinder'is operated from any suitable source of power, either electrical or mechanical. In such systems, considerable trouble is experienced in so controlling the hydraulic pressure to govern the grinder load as to prevent the so-called hunting action.

ed in accordance with my invention, hydraulic pressure is provided for applying the wood to the face of the grinder and an electric motor is provided for operating the grinder. A surge tank is connected to the hydraulic system adjacent to the main valve which controls the hydraulic pressure ap plied to the grinder.

' vents violent or sudden changes in hydraulic of motor may be utilized for such purpose.

A main control element, which is operated In a'grinder regulator system construct- Such surge tank pre-.

in accordance with the watts supplied to the main motor, is provided for operating two switches to selectively operate an auxiliary motor. The'auxiliary motor operates the mainvalve in the hydraulic system. The two switches not only control the auX- iliary motor but also control reactive forces which so affect the main control element as to prevent hunting action. The two separate means above set forth for preventing hunting action co-operate and insure the operation of the grinder with a constant load and without hunting action.

The single figure in the accompanying drawing is a diagrammatic view of a regulator system constructed in accordance with my invention. p

Referring to the drawing, a grinder 1, of. any suitable type, is connected to an alternating-current motor 2 in any suitable manner, as by means of a shaft 3. A hydraulic system 4 is provided for applying the load to the grinder 1 and a regulator system 5 is provided for controlling the operation of the hydraulic system 4 in accordance with the watts supplied to the main motor 2. The main motor 2 comprises a rotor 6,

which is directly connected to a three-phase supply circuit comprising conductors 7 and 8 and '9, and a field-magnet winding 10 which is energized from any suitable source of current.

The hydraulic system 41- comprises a loadapplying device 11-, a surge tank 13, a main gate valve 14, an auxiliarymotor 15 for operating the gate valve 14, and an anti-hunting device 16 for applying a reactive force to the gate valve 14. The load-applying device 11 comprises a compartment 17, containing the material 18 to be ground into pulp, and a piston head 19 which forces the ma-' terial 18 into engagement with the face of the grinder '1. The piston head 19 is connected by a rod 20 to a second piston head 21 which operates within a hydraulic cylinder 22. A valve 23, which operates within a pressure chest 24, is provided for applying hydraulic pressure above or below the piston head 21, as desired. The pressure chest 24- is supplied with hydraulic pressure by means of a pipe system 25.

The pipe system 25 is connected to a pipe 26 and the source of hydraulic pressure, either through a valve 27 or through the main valve 14. The auxiliary valve 27 is shower upon the grinder 1, are preferablyconnected directly to the pipe system 25 but, if so desired, any other connection to the source of hydraulic pressure may be utilized. The gate 33 of the main valve 14 is pivotally connected to a lever arm 34 which is 4 operated not. only by the motor 15 but also by the anti-hunting device 16. The motor 15 is mechanically connected to the lever arm 34 in any suitable manner, as by means of a rack and pinion 35, as shown in the drawing. The rack is connected to the lever arm 34 intermediate the connection of such lever arm to the gate 33 and to the anti-hunting device 16. A clockwise rotation of the motor 15 opens the valve 14 to decrease the load upon the grinder 1 and a counter-clockwise rotation of the motor closes the valve 14 to increase the load applied to the grinder 1.

The anti-hunting device 16 comprises a piston 36 which 0 crates within a hydraulic cylinder 37 an which is pivotally connected to the lever arm 34. A spring mem- .ber 38 is provided for opposing the action of the piston 36 and, a connection 39 is provided for connecting the cylinder 37 tothe hydraulic system intermediate the main valve 14 and the load-applying device 11.- The anti-hunting device 16 exerts a force tending to oppose any operation of the main valve to increase or to decrease the hydraulic pressure applied to the grinder 1.

The regulator system 5, which controls the operation of the auxiliary motor 15 in accordance with the watts supplied to the main motor 2, comprises a main control element 40' andtwo switches 41 and 42, which are controlled by the mainelement 40. The

main control element 40 comprises two elec-' "tromagnets 43 and 44 anda contact arm 45 which is jointly operated by the two electromagnets 43 and 44. I

The 'electromagnet 43 comprises two oppositely-wound current windings 46 and 47, a potential winding 48 and a core armature 49 which is pivota-lly connected to the contact arm 45. The electromagnet 44 comprises two oppositely-wound current windings 50 and 51, a potential winding 52 and a core armature 53, which is pivotally connected to the contact arm 45'.- The contact arm 45 carries a contact member 54, which is moved into engagement with stationary contact members 55 and 56, in accordance with the operation of the two electromagnets 43 and 44. A counterweight 90 is mounted on the contact arm 45.

The current windings 51 and 50 of the elec'tromagnet 44 and the current windings 46 and 47- of the electromagnet 43 are connected to two current transformers 57 and 58 in order to be energized in accordance with the current supplied to the motor 2. The current transformers 57 and 58 respectively comprise primary windings 59 and 60 and secondary windings 61' and 62. The primary windings 59 and 60 are connected to the three-phase conductors 7 and 9 and the secondary windings 61 and 62 are directly connected to the current windings of the electromagnets 43 and 44. A resistor 63. is connected across the secondary windings 61 and 62 for adjusting the strength of the current supplied to the current Windings of the electromagnets 43 and 44. The potential windings 48 and 52 of the electromagnets 43 and 44 are connected across the three-phase conductors 7 and 9. The windings'48 and 52 are connected to the threephase circuit in series with a resistor 64 and means is'provided for short-circuiting a portion of such resistor for preventing hunting action. Means isalso provided for shunting the two windings 48 and 52 by means of a second resistor 65 to prevent hunting action.

The two electromagnets 43 and 44 assist each other inoperating the contact arm -15 and each is operated in accordance with the Watts supplied to the main motor 2. The current windings of each electromagnet are oppositely wound and are symmetricallyv disposed with respect to the'associated core armature. The potential winding is disposed midway between the two current windings. The electromagnet 43 is assumed to raise the core armature 49 when energized and the electromagnet 44 is assumed to tend to lower the core armature 53 when energized. For a complete description as to the operation of such electromagnets,attention is directed to my companion application, Serial No. 378,731, filed May 4, 19-20.

The switch 41 comprises a coil 66, a core armature 67 and two switch members 68 and 69 and an interlock switch member 70, which are connected to the core armature 67. The switch 42 comprises a coil 71. a core armature 72, two switch members 73 and 74 and an interlock "switch member 75.

i A potential transformer 76, comprising a '42. The contact members 55 and 56 are respectively connected to the coils 71 and 66 01'' the switches 42 and 41. Thus,"upon engagement between the contact members 54 and 55, the coil 71 is energized 'for operating the switch 42, and, upon engagement between the contact members 54 and 56,

the coil .66 is energized for operating the switch 41.

One terminal of the auxiliar motor 15 is directl connected to the con uctor 9 and the ot er two terminals of the auxiliary motor are selectively connected across the conductors 7 and 8 by means of the switches -41 and 42. The switch members 68 and 69 of the switch 41 connect two terminals of the motor 15 to the conductors 7 and 8 for operating the motor in a counter-clockwise direction. The switch members 73 and 74 of the switch 42 connect two terminals of the auxiliary motor 15 across the conductors 7 and 8 for eifecting rotation of the motor in a clockwise direction. "The interlock switch member 70, upon operation of the switch 41, connects the resistor 65 in shunt to the two potential windings 48 and 52 of the main control device. tofprevent hunting action when the auxiliary motor is being operated in a clockwise direction. The interlock switch member 75, upon operation of the switch 42, serves to short-circuit a portion of the resistor 64 to prevent hunt-. ing action when the motor-is being operated in a counter-clockwise direction.

If the load upon the grinder 1 becomes abnormally. high, an abnormal number of watts is suppliedto the main motor2. Consequently, the electromagnets 43 and 44 are energized to effect engagement between the contact members 54 and 56. Upon engagement between the contact members 54 and 56, a circuit is completed from the" transformer 76 for operating the switch 41. Thereupon, the auxilia motor 15 is operated in a counter-clockwisedirection to close the main valve 14. Consequently, the hydraulic pressure supplied to the cylinder 22 for operating the piston 21 is reduced to lower the load on the grinder 1.

Upon change of fluid pressure in the hydraulic system between the main valve 14 and the device 11, the anti-hunting device 16 is operated to op ose the closing, operation of the main va ve 14. The hydraulic 7 pressure acting. upon the piston 36 is reduced and ,-.consequently, the spring member 38 tends to open the main" valve 14. Such operation of the anti-hunting-device 16 tends to anticipate 'the efl'ect on the regulator system of the decreased load upon the grinder 1.

Prior to the reduction in the'load upon the grinder 1 and simultaneous with the operation of the switch 41, the interlock switch member 7 O connects the resistor in shunt to the two potentialwindings 48 and 52 of the electromagnets 43 and 44 Thus, the

setting of the main control device 40 is changed and the electromagnets 43 and 44 are de-energized a certain amount to anticipate the reduction in load u on the grinder 1 and the main motor 2. I no such means were provided for changing the setting of. the electromagnets 43 and 44, the regulator would overtravel and cause the so-called hunting action. Consequently, the contact members54 and 56 are separated just prior to the -obtaining of normal load conditions upon the grinder 1.

If the load on the grinder 1 falls below normal value, the energization of the electromagnets 43 and 44 is reduced to effect enga ement between the contact members 54 an 55. Upon engagement between the contact members 54 and 55, the coil 71 is connected in circuit to the transformer 76 for operating the switch 42. Thereupon, the auxiliary motor 15 is operated in a clockwise direction to open the valve 14 and, accordingly, to in crease the hydraulic pressure which is ap plied to the load-applying device 11. Thereupon, the load carried by the grinder 1 and the motor 2 is increased.

The increase in pressure in the hydraulic system betweenthe valve 14 and the device 11 operates the anti-hunting device 16 to close the valve 14 and to oppose the action of the motor 15 in opening the valve 14.

The interlock switch member 75 shortcircuits a portion of the resistor 64 to increase the energization of the potential windings 48 and 52 and, consequently, to change the setting of the main control element 40. The energization of the electromagnets 43 and 44 is increased to effect separation of the contact members 54 and 55 just prior to the obtaining of normal load conditions on'the grinder 1. In such manner, hunting action on the part of the regulator is prevented.

In the above system, particular attention is called to the surge tank 13, the anti-hunting device 16 and the anti-hunting means associated with the regulator 5, all of which stafor reacting upon said valve to oppose its initial'operation;

2. In a regulator system, the combination with a grinder, a hydraulic system for applying the load to said grinder, avalve in said hydraulic system, and means for automatically controlling said valve to mainon said hydraulic means to prevent hunt- .for actuatin combination with a ing action. I

4. In a grinder regulator system, the

system for applying the load to said grinder,

a valve. in said hydraulic system for varying the pressure ap lied to said grinder, of means for contro ling said valve in accordance with the load supplied to said motor and including means. to prevent hunting action, and means operated in accordance with the pressure in the hydraulic system g said valve to prevent hunting action.

5. In a, grinder regulator. system, the

- combination with a grinder, a'main motor control for operating said grinder, a hydraulic systemfor applying theload to said grinder,

a valve forvarying the pressure on said hydraulic system to vary the load on the 5 grinder, and an, auxiliary, motor. for consaid' valve, of regulating means fortrolling ing said auxiliary -motor in accordance with the watts supplied to the main motor, means reacting on said regulatin means to prevent hunting 1 action, an

- means reacting directly on said valve to prevent hunting action. I 6. In a regulator system, the combination with agrinder, a main motor for operating said grinder, and means comprising I anv auxiliary motor for controlling theload appliedto said grinder, of means comprising two, electromagnets "operated in accordance with the watts supplied to the main motor for controlling the operation of said auxiliary motor, and means for vary-- ing the energization of said magnets to prevent hunting action,

- .7. Ina regulator system, the combination with a grinder, a three-phase supply circuit,

a motor connected to said circuit for operating said grinder, and means comprising an auxiliary motor for controlling the load on grinder, an electric motor for'operating said grinder, a hydraulic.

said grinder, of means comprising two electromagnets operated in accordance with the watts supplied to the main motor forvarying the connection of said auxiliary motor across the supply circuit to control the load on said grinder, and means for varying the ;the hydraulic pressure applied to the ygrinder, of a surge .tank.coimectedto the llydraulicsystem adjacent to said valve,

nieans for operating said valve in accordance with the load on thegrinder, and means reacting on said valve in accordance with'the hydraulic pressure applied to the grinder for preventing hunting action.

9. In a fluid-pressure regulatorsystem,

the'lcombination with means for varying the pressure ofsaid system to maintain prede .termlned normal pressure'therein, of additional means for preventing hunting action of said s stem com risin .means actin in y g g anticipation of the'return of normal pres- I l sure conditions, and means reacting inaccordance with the variations in saidpressure,

load, of regulator means for maintaining conditions, and additional ineans'reacting in accordance with the variation in said pressure, both of said last-mentioned meanscooperating to prevent hunting action.

11. In a regulator system, the combination with a grinder, a pressure system for applying load to said grinder, and means for automatically controlling said pressure system to maintain a constant load-upon said grinder, of means for preventing hunting ac- -tion of said regulator system adapted to'be actuated rior to the obtaining of normal load conditions and also coincidently with thereturn of normal load conditions L 12. In a regulator system, the combination comprising means adapted to have a load applied thereto, apressure system for applying said load, having a valve mechanism therein, av floating lever connected to said valve mechanism, a motor acting upon said lever to operate said valve, and means also 1 applied thereto, a pressure system. for, ap-. plying said load having a valve mechanism therein, a floating lever connected to said valve mechanism, meansfor automatically controlling said valve mechanism to main- 95' 10. In a regulator system, the combination. withfiuid-pressure meansfor applying a tain a substantially constant pressure, and

means co-operating with. said'fioating lever to react upon said valve mechanism to ,prevent hunting action.

14. In a regulator system, the combination with a grinder, means for applying load thereto, and an electric motor for operating said grinder, of regulating means comprising a pair of electromagnets operated in accordance with the Watts of said motor circuit, and each comprising a pair of oppositely-disposed current coils and a centrally-located voltage coil, said coils co-operatin with a sin 'le core armature a lurality of switches controlled thereby having 4 interlock memberserespectively co-operating v therewith, and a plurality of resistors controlled by said interlock members to vary the settings of said electromagnets 15. In a regulator system, the combination with a grinder and means for applying load thereto, of means for correcting for variations in said load and comprising antihunting means reacting in accordance with corrections for said variations, and additional anti-hunting means acting in anticipation of the full correction for said load variations.

16. regulator system, the combination with a grinder, pressure means for applying load thereto, and anelectric motor for operatlng sald grinder, of regulator means therefor comprising an electromagnet connected to said motor circuit and having a pair of oppositely-disposed current coils and a centrally-disposed voltage coil, a plurality of switches, and anti-hunting means having an anticipatory action and comprising a resistor controlled by said switches.

17. In a regulator system, the combination with a grinder, pressure means for applying load thereto, and an electric motor for operating said grinder, of regulator; means therefor comprising an electromagnet connected to said motor circuit and having a pair of oppositely-disposed current coils and a centrally-disposed voltage coil, a plurality ofswitches, anti-hunting means having an anticipatory action. and comprising a resistor controlled by said switches, and additional anti-hunting means having a reactive action in accordance with the variations in said pressure system.

In testimony whereof, I have hereunto subscribed my name this 8th day of September, 1920. 

